An exploration on the improvement of reversible conversion and capacity retention of Sb2O3-based anode materials for alkali metal-ion storage by Fe-C co-hybridization

Herein, an optimized SFC-2 sample with excellent electrochemical performances as anode material for alkali metal-ion batteries via regulating a series of ternary composites of Sb 2 O 3 -Fe-C (SFC) prepared by ball milling is achieved. Due to the co-existence of Fe (20 wt%) and conductive carbon (10 wt%), the SFC-2 electrode exhibits outstanding electrocatalytic effects, which can make the alkaline metal ions transfer fast and accelerate the redox reactions. DFT calculation results further demonstrate Fe acting as a catalyst, which can catalyze the breaking of Sb-O bonds and Li-O bonds and reduce their binding energy, thus improving initial Coulombic efficiencies (ICEs) of the materials. As a result, the SFC-2 electrode releases a high specific capacity of 919 mA h g −1 with a high ICE of 83.8% at 0.5 A g −1 for lithium ion batteries (LIBs), which also has excellent electrochemical performances for sodium ion batteries (SIBs). • Fe and carbon co-doped Sb 2 O 3 composite is fabricated via a facile ball-milled route. • Synergy of Sb 2 O 3 and carbon enhances structure stability and electrical conductivity. • Conductive metallic Fe could improve the reversibility of the conversion reaction.